#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>
#include <assert.h>

char* my_strcat(char* des,const char* source)
{
	assert(des && source);
	char* ret = des;
	while (*des++)
	{
		;
	}
	des--;
	while (*des++ = *source++)
	{
		;
	}
	return ret;
}

int main()
{
	char arr1[20] = "hello ";
	char arr2[] = "alison";
	my_strcat(arr1, arr2);
	printf("%s", arr1);
	return 0;
}